Visual display of complex color television sound wave signals

ABSTRACT

This disclosure involves apparatus and modifying circuits for use in conjunction with a conventional color cathode-ray tube to provide fanciful wide-band vector representations of the video signals by a pair of audio channels such, for example, as would be produced with a stereophonic recorded-signal source. The stereophonic signal source may be generated through microphones, phonograph and magnetic tape recordings, or from stereophonic broadcasts and is amplified and processed by wide-band linear circuitry whose effect is substantially independent of frequency and displayed in vector form on a color cathode-ray tube utilizing magnetic deflection. The effect of the apparatus is to produce highly detailed visual patterns of great regularity and beauty of form and color, revealing fine details inherent in the stereophonic representation of the complex, nonrecurrent wave forms produced by music or voice. No filters or frequency sensitive elements are used except as required to enhance the signal-to-noise ratio of the program material in which no timing signal, sweep signal, or raster representation is employed.

United States Patent [72] Inventor William E. Hearn Atherton, Calif. [21] Appl. No. 818,666 [22] Filed Apr. 23, 1969 [45] Patented Dec. 14, 1971 [73] Assignee Charles W. Kieser San Francisco, Callll. a part interest [54] VISUAL DISPLAY OF COMPLEX COLOR TELEVISION SOUND WAVE SlGNAlLS 7 Clalrn's, 4 Drawlng Figs.

[52] 11.8. C1. 173/521 1%, 179/1 VS [51] Int. Cl. 1110411 9/112 [50] Fleld 01 Search 178/54; 179/1 V',84/l.18CR, 1.12, 1.21, 1.22; 315/23; 343/5 [56] References Cited UNITED STATES PATENTS 3,175,121 3/1965 Birnbaum 315/23 2,275,283 3/1942 Burchfield. 179/1 2,804,500 8/1957 Giacolletto.... 178/54 2,989,582 6/1961 Zworykin et a1 168/54 3,175,121 3/1965 Birnbaumetal. 3,307,142 2/1967 Doebler ABSTRACT: This disclosure involves apparatus and modifying circuits for use in conjunction with a conventional color cathode-ray tube to provide fanciful wide-band vector representations of the video signals by a pair of audio channels such, for example, as would be produced with a stereophonic recorded-signal source. The stereophonic signal source may be generated through microphones, phonograph and magnetic tape recordings, or from stereophonic broadcasts and is amplified and processed by wide-band linear circuitry whose effect is substantially independent of frequency and displayed in vector form on a color cathode-ray tube utilizing magnetic deflection. The effect of the apparatus is to produce highly detailed visual patterns of great regularity and beauty of form and color, revealing fine details inherent in the stereophonic representation of the complex, nonrecurrent wave forms produced by music or voice. No filters or frequency sensitive elements are used except as required to enhance the signal-tonoise ratio of the program material in which no timing signal, sweep signal, or raster representation is employed.

JETECTUR RED 49:5 :BLUE

? inset/aver PATENTEU nu: I 4 ram SHEET 1 OF 2 VISUAL DllSPLAY OF COMPLEX COLOR TELEVISHON SOUND WAVE SlGNAlLS A primary object of the invention is to provide apparatus and a system of control for a color cathode-ray tube by which signal voltage. Likewise, the function of A with its feedback resistor R provides a signal current in the Y-deflection yoke which is also proportional to the input signal voltage. This ensures that the electron beam will be deflected proportionally a fanciful wide-band vector representation in color of the to h input voltage Th lifi A d A are power Vide Sighais Produced by the audio ehahheis of a plifiers with differential inputs and large voltage gain, and are stereephehie recorded Bh obtains? typically capable of delivering at least 1 ampere of signal cur- Ahoihei' ohleci Of the ihvehhoh is Provide a modifying rent into a l0 ohm load and are connected in a potentiometric circuitry for a CRT which analyzes the P i'esuiiahi feedback configuration to ensure constant current operation. velocity of the trace upon a color TV screen with instantane- It is seen that by means of the abowe arrangement n Com ous Z modulation of the color of the trace throughout a broad "01 may be exercised over the average xiv/r), ratio of the spectrum ofcolor as a function of the i when)" patterns displayed by means of dual control R and R while I am aware of Q Q 2500646 Rlesz dated f full control may be exercised over the average x/y ratio of the 1 4, I950, Which-1S primarily concerned with blaclc and white patterns displayed by dual control R3 and R4 and fun comm. signals and, while this patent proposes apparatus in some may be obtained over the average size of the patterns disrespects similar tothe present invention, its operation depends played by dual comrol R5 R6 A feature of this g upon the assumption that the input material is from a single h u f f t I h channel which contains stable frequency information. mem t at a 9 or coffee 0 9 ma ena w A somewhat similar proposal for black and white reproducmay be deficient m separanm, as well as m balanfie thinetion is found in US 3,175,121 w mmmum, issued fore provides a means of ad usting for symmetrical distribu- Man 23' [965 which proposes apparatus to provide for the tion of the patterns displayed along the x+y/xy axes as well as display of rosette panemi This patent depends for operation along the x/y axes. The signals developed at the output of dual upon two sine-wave generators, harmonically related, whereas comm] Rb and R6 are amplified applied to the color in accordance with this invention no such related wave caihodfi'ray f and deflection Foils by mefms 0f generators are required 2 deflection amplifiers A and A; which linearly amplify the It is further object of my invention to provide apparatus and ihlilht Signal and Provide for an p p relation circuitry differing from the above prior art by which a fanciful p between the X-amPlifier input Sisnal and the p wide-band vector representation in color of the video signals is Them of the p the Screen, and a simiiai'iy Proportional produced by astereophonic signal source. relationship between the Y-amplifier input signal and the Y- Other objects and advantages will be in part evident to those displacement of the trace upon the screen. Deflection amskilled in the art and in part pointed out hereinafter in the folplifiers A and A provide for this proportional relationship lowing description taken in connection with the accompanyover the full range of frequencies of interest so that the coning drawings wherein there is shown by way of illustration and figuration of the pattern produced in independent of the not of limitation a preferred embodiment of the invention. In frequency, if any, of the program material. The circuitry the accompanying drawings: which provides the Z-modulation for the trace color is also 1 is a Schematic diagram Showing the invention as P- shown in H6. 1 of the drawings and operates as follows: Let Piied to a eohvehtiohai CRT tuber the position of the trace upon the screen be defined as a func- FIG. 2 is a diagram showing the X- and Y-axes of a display i f i b h l i hi as contemplated by the invention, PX) =ym F IG. 3 is a further diagrammatic showing of the circuits emwhere h center f h RT Screen i assumed to be at =0 ployed in the color modulator as employed in accordance with y= iheihvehiiohiahd With this it will be seen that, in the circuitry shown, the f FIG. 4lshowts Lhe input voltage curves as related to the difmagnitude of Velocity Ofthe trace is given by erent co orso t e spectrum. 2

For a detailed description of the invention reference is now h |V|-- i Vx +Vy made to FIG. 1 of the accompanying drawings wherein there is w are I diagrammatically shown a conventional color cathode-ray Xu) i tube ill) having cathodes ill, a filament supply 12, screen and supply source 13, a focus supply 14 and a highvoltage supply 5 15 for the screen. ln this showing deflection coils X and Y are A Signal propei'iiehai the above Weioeiiy maghiiiide V is shown as included in a circuit connected to input channels A Used to modulate the eeioi- The effect of the circuitry is and B AS here shown h input h l A d B are b f. to cause the patterns displayed to be multicolored. In displayfered by amplifiers A and A and applied to dual-control reing any given pattern, the trace velocity may go through a sistances R and R which consists of two counterrotating velocity variation in excess of two orders of magnitude. The potentiometers that provide a balancing of the input channels circuitry will cause the trace to have a red hue at lower veloci- A and B. The outputs of dual-control resistances R and R are ties, changing to orange as the velocity increases, and changmatrixed by a linear matrix 16 which accepts the input signal ing through yellow, green, blue, violet and intermediate spevoltages of channels A and B on its two input terminals and cial colors with further increases in velocity.

produces at its two outputs the output signal voltages A+B and The color modulator is designed to provide varying amounts A-B. These two output signals may be termed the sum and of drive to the red, green and blue grids of the tricolor CRT so difference" signals respectively. Dual Control resistances a as to accomplish the above relationships. The embodiment of and 4 consist of We eeumeh'otaiihg liieliehliomeiers which the circuitry of the color modulator is shown in FIG. 3. This Provide for a haiaheihg of the Si-im and difference sighaie- The modulator has for its input signal the velocity signal derived by euipui of this eohii'oi is bhffei'ed by ampiiiiei's ri and 4 and means of performing the following operations on the displace- PP duai cohh'ois R5 and which aiso cohsisi of two ment signals X(t) and Y(!) which are the drive signals to the potentiometers that rotate in step and provide for varying the a fl i fifi A5 and signal level input to the two deflection amplifiers A and A 1 Diffe entiate XU), Y(i) to get (9(1), l (l) Ampiifiei's Ah 2 A3 and A4 are Voltage amplifiers having 2. Take absolute value of X'(t) and 'l (t) to get I )fU) and high-input impedance and low-output impedance. This means 701 fl that they do not appreciably load the circuit which drives them and they present a very firm voltage source when driving 3.Square Uh!) l and l l toget lJfUHand U h) I 4. Takethesum of Ufflfl and' 11%!) to at I)?! t 2 other circuits. lt is the function of A in combination with its l g )i l W )l feedback resistor R to provide a signal current in the X- deflection yoke which is directly proportional to the input 5. Take the square root of H20 2 l(t)lto get \/.(l) +i(!) as indicated on the drawing.

Other novel elements of the display are the blanking detector 18, the luminance amplifier l9, and Z modulation oscillator 20. The blanking detector 18 examines the signal current in the deflection yoke which is proportional to the displacement of the trace upon the screen and generates an electrical signal which causes the electron beam intensity to decrease to the black level when the beam is not being deflected and is occupying the center of the screen. Decreasing the beam intensity in this way prevents the phosphor at the center of the CRT from being burned by the continuous application of the highintensity electron beam.

The purpose of the Z modulation oscillator 20 is to generate a signal of relatively high frequency (on the order of 100 kHz.) which is used to continuously modulate the electron beam intensity. This has the effect of giving a dotted quality to the display, increasing the ease with which certain patterns may be distinguished. The color modulator circuit accepts at its input a voltage which is proportional to the velocity of the trace upon the screen. From this input signal it must generate three output voltages, a red, a green and a blue voltage which are used to drive the control grids of the color cathode-ray tube. Ideally this circuit will generate these three output voltages in such a way that the proportions of red, green and blue vary so as to produce a resultant trace color which changes through the whole spectrum as the input voltage (proportional to trace velocity) varies from zero to some maximum value.

Preceding this, the function of the differentiators is to accept the input signal voltages which are proportional to the displacement of the trace upon the screen and to produce at their output a velocity signal which is proportional to the time derivative of the input signal voltages and thus is also proportional to the time derivative of the beam displacement or velocity.

The absolute value circuit accepts the input voltage which is proportional to the velocity of the trace upon the screen and generates at its output a voltage equal in magnitude to that of the input, but having only a single polarity. For example, if the input voltage goes i 1 volt above and below ground, indicating that the beam is moving at positive and negative velocities, the absolute value circuit will generate 1 volt in each case. Note that the direction of motion is unimportant, but the magnitude is to be used to modulate the color.

lt is the function of the square circuit to accept the input voltage which is proportional to the magnitude of the velocity of the trace upon the screen and to generate at its output a voltage which is proportional to the square of this input voltage and hence is proportional to the square of the velocity of the trace upon the screen.

The function of the summing circuit is to add the two input voltages and produce at the output a voltage equal to the sum of the two input voltages.

It is the function of the square root circuit to generate at its output a voltage equal to the square root of the voltage present at the input. It is seen that the signal developed by means of the above procedure is exactly proportional to the velocity of the trace upon the screen. Control R is used to adjust the velocity signal which is applied to the color modulator The color modulator l7 circuit accepts at its input a voltage which is proportional to the velocity of the trace upon the screen. From this input signal it must generate three output voltages: a red, a green and a blue voltage which are used to drive the control grids of the color cathode-ray tube. Ideally this circuit will generate these three output voltages in such a way that the proportions of red, green and blue vary so as to produce a resultant trace color which changes through the whole spectrum as the input voltage (proportional to trace velocity) varies from zero to some maximum value.

ln the circuit shown in FIG. 3, the three color output voltages are generated by three identical circuits, each of which is ages. This can be shown graphically by the three output vs.

in ut curves as shown in FIG 4.

he function of the blanking detector is to examine the displacement signals x(t) and y(t) and produce an output signal only when x(z) and y(t) have been zero for some length of time; i.e., when the trace is stationary at the center of the screen and the phosphor is in danger of being burned by the high-intensity beam. This output signal will be used to shut off the beam to avoid burning the center of the color CRT screen.

The Z modulation oscillator 20 circuit turns the beam on and off at a very rapid rate which lends a grainy" or dotted" quality to the display. This is done for purely esthetic reasons. It appears to enhance the patterns produced. The luminance amplifier 19 is a simple video amplifier of the type often used in TV sets. It reacts to the input voltages from the blanking detector and Z-modulation oscillator by modulating the cathode current of the CRT.

While I have shown and described a single embodiment it -will be apparent that many changes may be made in the apparatus without changing the essential features of my invention; for example, the deflection amplifiers need not be operated by means of constant current feedback as shown in FIG. 1, but may be operated as voltage sources if properly equalized to obtain constant current operation. Also, the three red, green and blue color signals used to drive the grids of the tricolor CRT may be derived'by means of different circuitry and still give a similar effect; for example, in place of the velocity modulation used to develop the three color signals, the audio spectrum may be split into three bands and the energy in each band may be detected and used to generate the three red, green and blue color signals.

Although I have shown and described a certain specific embodiment of my invention, 1 am fully aware that many modifications thereof are possible. My intention, therefore, is not to be restricted except insofar as is necessitated by the prior art and the spirit of the appended claims.

Having thus described my invention, what l claim and desire to secure by Letters Patent is:

1. Apparatus utilizing a color cathode-ray tube (CRT) having X- and Y-deflection means and three color grid means to provide a colored screen pattern of the information contained in two stereophonic input signals comprising: first means responsive to said two input signals for driving said X and Y means and providing a CRT beam displacement proportional to said two input signals; and second means responsive to said two input signals for providing a modulation signal proportional to the velocity of said beam displacement for driving said grid means.

2. Apparatus as in claim 1 where said second means includes modulating means responsive to three different but overlapping ranges of said modulation signal to produce three color grid control voltages. v

3. Apparatus as in claim 1 where said first means includes means for matrixing said two input signals.

4. Apparatus as in claim 3 where said second means is responsive to said matrixed signals.

5. Apparatus as in claim 3 where said matrixing means includes means for balancing said two input signals.

6. Apparatus as in claim 1 where said second means includes analog circuit means for causing said modulation signal to be proportional to the absolute velocity of said beam dis placement.

7. Apparatus as in claim 6 where said analog circuit means includes means for differentiating said input signals, taking the absolute value of such differentiated signals, squaring said absolute values, summing said squared values, and taking the square root of said sum, said square root signal being said modulation signal. 

1. Apparatus utilizing a color cathode-ray tube (CRT) having Xand Y-deflection means and three color grid means to provide a colored screen pattern of the information contained in two stereophonic input signals comprising: first means responsive to said two input signals for driving said X and Y means and providing a CRT beam displacement proportional to said two input signals; and second means responsive to said two input signals for providing a modulation signal proportional to the velocity of said beam displacement for driving said grid means.
 2. Apparatus as in claim 1 where said second means includes modulating means responsive to three different but overlapping ranges of said modulation signal to produce three color grid control voltages.
 3. Apparatus as in claim 1 where said first means includes means for matrixing said two input signals.
 4. Apparatus as in claim 3 where said second means is responsive to said matrixed signals.
 5. Apparatus as in claim 3 where said matrixing means includes means for balancing said two input signals.
 6. Apparatus as in claim 1 where said second means includes analog circuit means for causing said modulation signal to be proportional to the absolute velocity of said beam displacement.
 7. Apparatus as in claim 6 where said analog circuit means includes means for differentiating said input signals, taking the absolute value of such differentiated signals, squaring said absolute values, summing said squared values, and taking the square root of said sum, said square root signal being said modulation signal. 